Process for treating gaseous products obtained by thermal cracking of hydrocarbons

ABSTRACT

A process for removing from a cracked gas product carbon and tar contained therein, which comprises spouting a high temperature cracked gas product containing carbon and tar, formed by thermal cracking of a hydrocarbon, from the bottom of a vessel in which inorganic solid particles are contained, thus forming a spouted bed of the solid particles in the vessel, and spraying water or a liquid hydrocarbon in the so formed spouted bed of the solid particles to thereby quench the cracked gas product and to simultaneously allow the carbon and tar contained in the cracked gas product to stick and adhere onto the surface of the solid particles.

United States Patent [191 Suzukawa et a1.

[54] PROCESS FOR TREATING GASEOUS PRODUCTS OBTAINED BY THERMAL CRACKINGOF HYDROCARBONS [22] Filed: March 23, 1971 [21] App1.No.: 127,224

Ube-shi [52] US. Cl ..55/9l, 55/233 [51] Int. Cl. ..B0ld 47/06 [58]Field of Search ..55/77, 79, 84,90, 91, 233,

[5 6] References Cited UNITED STATES PATENTS 3,581,473 6/1971 Ririe,.1r..55/233 1 March 6, 1973 Primary Examiner-Charles N. HartAttorney-Sherman and Shalloway 5 7 ABSTRACT A process for removing froma cracked gas product carbon and tar contained therein, which comprisesspouting a high temperature cracked gas product containing carbonandtar, formed by thermal cracking of a hydrocarbon, from the bottom of avessel in which inorganic solid particles are contained, thus forming aspouted bed of the solid particles in the vessel, and spraying water ora liquid hydrocarbon in the so formed spouted bed of the solid particlesto thereby quench the cracked gas product and to simultaneously allowthe carbon and tar contained in the cracked gas product to stick andadhere onto the surface of the solid particles.

6 Claims, 6 Drawing Figures PATENTFUMM: @1975 37,719,029

SHEET 2 or 3 Fig.2

ff Fig.3

Fig. 4

SHEET 3 or 3 Fig. 5

PROCESS FOR TREATING GASEOUS PRODUCTS OBTAINED BY THERMAL CRACKING FHYDROCARBONS This invention relates to a process for treating crackedgases of hydrocarbons, which comprises treating a high temperaturecracked gas containing carbon and tar, which is formed by thermalcracking of a hydrocarbon, especially a heavy liquid hydrocarbon such ascrude oil and heavy oil, in a spouted bed of solid particles, quenchingthe cracked gas and simultaneously removing carbon and tar efficientlyfrom the intended gas components such as hydrogen, methane, acetylene,ethane, propylene, propane, butene, butadiene and carbon monoxide.

Methods of preparing olefins such as ethylene, propylene, butene andbutadiene and hydrogen and the like by thermally cracking hydrocarbonssuch as crude oil, heavy oil, naphtha and natural gas at hightemperatures have been known. High temperature cracked gases formed bysuch thermal cracking contain considerable amounts of carbon and tar,though their contents vary to some extent depending on the kind ofhydrocarbon cracked, the cracking procedure, the cracking conditions andother factors.

In the thermal cracking of hydrocarbons, in order to prevent occurrenceof undesired side-reactions which decrease the yield of intended gascomponents and increase amounts of undesired by-products, it isnecessary to quench the high temperature cracked gas from the crackingreactor. During such quenching treatment carbon and tar contained in thecracked gas adhere to the quenching apparatus and are deposited thereon,which makes the quenching operation difficult or impossible. Not onlyfor this reason, but also to obtain a refined gas, it is necessary toremove carbon and tar from the cracked gas.

Accordingly, various proposals have been made as to methods of quenchinghigh temperature cracked gases and methods of removing carbon and tarfrom them, and many proposals are actually practiced industrially. Forinstance, a method is practiced comprising introducing a hightemperature cracked gas into a heat exchanger or the like, quenching thecracked gas and simultaneously recovering the enthalpy of the crackedgas, washing the gas with water or a liquid hydrocarbon to therebyremove carbon and tar, and introducing the washed gas into the refiningprocess.

Although such method is applicable to the treatment of cracked gasesobtained by thermally cracking light hydrocarbons such as naphtha, whenthis method is applied to cracked gases of high contents of carbon andtar obtained by the thermal cracking of heavy hydrocarbons such as crudeoil and heavy oil, carbon and tar adhere to the heat exchanger and aredeposited thereon, with the result that the operation is madeimpossible. This is the fatal defect of the above method.

In the specification of Japanese Pat. Application Publication No.41/19886 a method is proposed comprising contacting a cracked gas withlarge amounts of water and a liquid hydrocarbon in a counter-currentmanner to thereby wash the cracked gas, and thus quench the same andsimultaneously remove carbon and tar. This method is, however, defectivein that great amounts of water and liquid hydrocarbons must be used andit is necessary to refine great amounts of water and liquid hydrocarbonscontaminated with carbon and tar before their recycle, which requiresgreat expense and results in a great economical disadvantage.

From the specification of Japanese Pat. Application Publication No.40/8329 a method is known comprising introducing a high temperaturecracked gas obtained by the thermal cracking of, for instance, crude oilinto a cyclone, and washing it with a liquid 0 hydrocarbon to cool thegas and remove carbon and tar therefrom. Also in this method, carbon andtar tend to adhere to the cyclone and are easily deposited thereon.Further, in this method, since the cracked gas is cooled by evaporatingthe liquid hydrocarbon in a washing column, it is necessary to use alarge amount of liquid hydrocarbon as in the above-mentioned method. Forthese reasons, this method is also defective.

Apart from the conventional concept of removing carbon and tar containedin a gaseous product comprising hydrogen, methane, ethylene, ethane,propylene, propane, butene, butadiene, carbon monoxide, carbon dioxide,oxygen, nitrogen, light oil, heavy oil, tar, carbon and steam, obtainedby the thermal cracking of a hydrocarbon by contacting the gaseousproduct with a suitable washing liquid and thereby washing out carbonand tar from the gaseous product, research has been conducted and it hasbeen found that when such gaseous product is cooled in a spouted bed ofsolid particles and simultaneously contacted with fluidized solidparticles, carbon and tar components contained in the gaseous productare efficiently caught on the surfaces of solid particles, wherebycarbon and tar components can be efficiently removed from the gaseousproduct without forming any contaminated washing liquid.

The primary object of this invention is to provide a process for easilyremoving carbon and tar simultaneously from a high temperature crackedgas obtained by the thermal cracking of a hydrocarbon, especially aheavy liquid hydrocarbon such as crude oil and heavy oil, in which suchhigh temperature cracked gas is introduced into a spouted bed of solidparticles, water or a liquid hydrocarbon is sprayed into the spoutedbed, the cracked gas is quenched by utilizing the latent heat ofvaporization of water or the liquid hydrocarbon and at the same timecarbon is efficiently allowed to stick to the solid particles of thespouted bed by utilizing the adhesiveness of tar.

Another object of this invention is to provide a process for removingcarbon and tar from a cracked gas product obtained by the thermalcracking of a hydrocarbon by quenching such cracked gas product of ahigh temperature without using a washing liquid, namely withoutformation of a great amount of a waster contaminated washing liquid.

in accordance with this invention, a process is provided for removingfrom a cracked gas product carbon and tar contained therein, whichcomprises spouting a high temperature cracked gas product containingcarbon and tar, formed by the thermal cracking of a hydrocarbon, fromthe bottom of a vessel in which inorganic solid particles are contained,thus forming a spouted bed of the solid particles in the vessel, andspraying water or a liquid hydrocarbon in the so formed spouted bed ofthe solid particles to thereby'quench the cracked gas product and tosimultaneously allow the carbon and tar contained in the cracked gasproduct to stick and adhere onto surfaces of the solid particles.

Any of the cracked gases formed by the thermal cracking of hydrocarbonscan be treated in the process of this invention. For instances, crackedgases formed by the thermal cracking of crude oil, heavy oil, naphtha,natural gas and methane may be treated in the process of this invention.These cracked gases inevitably contain carbon and tar in addition tovaluable substances such as methane, acetylene, ethylene, ethane,propylene, propane, butene, butadiene, hydrogen and carbon monoxide. Theprocess of this invention is suitable for the treatment of cracked gasesof high carbon and tar contents obtained by the thermal cracking ofheavy liquid hydrocarbons such as crude oil and heavy oil, especiallyfor the treatment of cracked gases containing carbon and tar in a totalamount of -100 g/Nm.

These cracked gas products are generally withdrawn in the state heatedto 7001,400 C. In this invention, quenching of cracked gas products ofsuch high temperatures withdrawn from a cracking reactor and removal ofcarbon and tar are effectively accomplished.

It is important that the treatment according to this invention isconducted in a spouted bed or inorganic solid particles. By the termspouted bed used in the specification and claims is meant an ordinaryspouted bed employed in the art, namely the bed of solid particles inwhich the solid particles are fluidized and forcibly circulatedconvectively in a vessel by injecting a fluid from a spout provided atthe bottom of the vessel without a perforated gas distributor.

When a cracked gas product is treated in an ordinary fluidized bed,carbon and tar contained in the gas product adhere to a perforated gasdistributor and choking of the distributor is frequently caused tooccur. This disadvantage may be overcome if a refined cracked gas orsteam is used for fluidizing solid particles. However, anotherdisadvantage is brought about in that such refined cracked or steam mustbe usedin great quantities. According to this invention thisdisadvantage is also overcome effectively by the use of a spouted bed.

As inorganic solid particles to be used for formation of a spouted bed,particles of any optional refractory material may be used. For instance,particles of inorganic solid substances such as mullite, alumina-silica,cement clinker, magnesia clinker and alumina may be used conveniently inthis invention. Among them, mullite or alumina-silica particles areespecially preferred because they resist a vigorous temperature changeand the violent friction which they should encounter is the spouted bed.It is desired that these particles have a diameter of 0. l'-6 mm,especially 1.5-4 mm.

The optimum temperature of the spouted bed varies depending on the kindand composition of the cracked gas to be treated, the contents of carbonand tar and the like. Accordingly, the optimum temperature cannot besimply determined based on one factor or other. However, it is generallypreferably that the spouted bed is maintained at 200-600C, especially300-500 C. It has been found that tar having a boiling point slightlyhigher than the bed temperature tends to be easily caught on particlesof thespouted bed.

The superficial gas velocity in an empty column, U0 (m/sec), of thecracked gas in the spouted bed is adjusted depending on the averagediameter of the solid particles in the bed, the size distributionthereof, the heat transfer velocity in the bed and other factors, but inorder to attain a good spouting state it is generally preferable tomaintain the superficial gas velocity in an empty column at 1-10 m/sec,especially 2-5 m/sec.

The velocity of the cracked gas at the spout must be higher than theterminal velocity of the solid particles in the spouted bed. Whenparticles of a diameter of 1.5-4.0 mm are used, it is desired tomaintain the velocity of the cracked gas at the spout within a rangeoffrom 20 m/sec to 30 m/sec.

The ratio of the superficial gas velocity in an empty column, Uo(m/sec), to the superficial gas velocity at minimum fluidizingconditions, Umf (m/sec), namely the ratio of Uo/Umf, is adjusted withina range of from 1.5 to 10, preferably from 2 to 8.

With regard to the liquid hydrocarbon to be sprayed in the spouted bedfor quenching the cracked gas product, it is preferable to use thosehaving a boiling point lower than about C. when the process is conductedat the bed temperature of 200-300 C. andto use those having a boilingpoint not exceeding about 250 C. when the process is conducted at thebed temperature of 300-600 C. In view of the effect of quenching thecracked gas and from the economical view point, it is desired to sprayinto the spouted bed water which has a great latent heat of vaporizationand is easy to handle. Water or a liquid hydrocarbon is sprayed singlyfrom an optional position of the spouted bed but a better diffusion ofthe sprayed liquid is attained by spraying the liquor from the lowerportion of the spouted bed at a velocity higher than that of the crackedgas with use of steam or refined cracked gas. By such spraying,quenching of the high temperature cracked gas and sticking of carbon andtar onto the solid particles can be effectively accomplished.

The amount of the-'quenching liquid to be fed to the spouted bed variesto some extent depending on the latent heat of vaporization possessed bythe quenching liquid, the temperature and specific heat of the crackedgas to be treated, the intended bed temperature and other factors.However, better results are obtained when the amount of quenching'liquidfed is so adjusted that the bed temperature will be within a range offrom 200 to 600 C., preferably, from 300 to 500 C.

This invention will now be detailed by referring to accompanyingdrawings.

FIG. 1 is a diagram illustrating an example of the arrangement of aseries of devices suitable for practice of the process of this inventionand equipment for regenerating solid particles.

FIG. 2 is a diagram illustrating the longitudinal section of anotherexample of the apparatus suitable for the practice of the procof thisinvention.

FIG. 3 is a plane view illustrating a baffle to be adapted to theapparatus of FIG. 1 or 2 suitable for the practice of the process ofthis invention.

FIG. 4 is a perspective view illustrating an example of the member ofFIG. 3 adapted to the apparatus suitable for the practice of the processof this invention.

FIG. 5 is a side view showing still another embodiment of the apparatussuitable for the practice of the process of this invention.

In FIG. 1, solid particles regenerated in a hopper 5 are fed from aconduit 3. If required, fresh solid particles are fed from a conduit 4.Then, the particles are fed into a spouted bed type quenching vessel 1through a valve 6 and a conduit 7.

Also a high temperature cracked gas formed in a cracking reactor (notshown) by the thermal cracking of a hydrocarbon is introduced to thespouted bed type quenching vessel 1 through a conduit 2 and injectedinto the vessel 1 at a prescribed velocity from a spout 9 positioned atthe bottom of the vessel 1. By this injection of the cracked gas thesolid particles in the spouted bed type quenching vessel 1 are fluidizedand move upwardly together with the cracked gas in the central portionof the vessel 1. Then, the solid particles descend in the inner wallportion of the vessel 1. In this manner, the solid particles areforcibly circulated in the vessel 1 convectively and a spouted bed S ofsolid particles is formed.

A quenching liquor composed of water or a liquid hydrocarbon is sprayedinto the spouted bed S of the spouted bed type quenching vessel 1through a conduit 12 from a nozzle 13 positioned in the lower portion ofthe spouted type quenching vessel 1 with the aid of steam or refinedcracked gas injected from conduits l0 and 11, and the high temperaturecracked gas fed from the spout 9 is quenched by the latent heat ofvaporization of the so sprayed water or liquid hydrocarbon. At the sametime, the temperature of tar contained in the cracked gas is kept belowthe boiling point thereof by the above quenching and is allowed to stickand adhere onto surfaces of the solid particles in the spouted bed S,while carbon is efflciently caught on surfaces of the solid particleswet with deposited tar due to its adhesiveness.

The cracked gas which has been quenched by the above operation and fromwhich carbon and tar have been removed is introduced as the treatedcrackedgas to the last refining process (not shown) through a con-' duit8 positioned in the upper portion of the spouted type quenching vessel1.

It is preferable that the bottom wall of the spouted type quenchingvessel 1 has a frustoconical configuration of an inclination angle of30l20, especially 60-90 and that the spout 9 is position at the centerof this frustoconical bottom wall.

Solid particles in the spouted bed S to which carbon and tar have stuckare continuously withdrawn outside the spouted bed type quenching vessel1 through a conduit 14 connected to the side wall of the spouted bedtype quenching vessel 1 via a valve 15.

Another spouted bed type quenching vessel suitable for the practice ofthe process of this invention will now be explained by referring to FIG.2.

In FlG.-2, solid particles are fed into a spouted bed type quenchingvessel 39 from a conduit 38 and a high temperature cracked gas from aspout 41 via a conduit 40. In this way, a spouted bed 8' is formed inthe spouted bed type quenching vessel 39 by fluidization of the solidparticles.

Water or a liquid hydrocarbon is sprayed into the spouted bed typequenching vessel 39 from a nozzle 43 via a conduit 42 with an aid ofsteam or refined cracked gas injected through conduits 44 and 45, and bythe latent heat of vaporization of the so sprayed water or liquidhydrocarbon, the high temperature cracked gas is quenched. At the sametime, carbon and tar are allowed to stick to the surfaces of the solidparticles in the spouted bed S in a manner as described above.

The cracked gas which has been quenched and from which carbon and tarhave been removed is withdrawn from a conduit 46 and introduced to thelast refining process (not shown).

As to the solid particles in the spouted bed S to which carbon and tarhave sticked, only coarsened particles having a diameter exceeding acertain level are selectively caused to descend from a spout 47 in aconduit 48 toward a hopper 49 by steam or refined cracked gas projectedinto the spouted bed 8' from the spout 47 via a conduit 50, the hopper49 and the conduit 48 positioned beneath the spouted bed type quenchingvessel 39,- according to the so-called elutriation principle. Inconducting the above operation, it is necessary to feed steam or refinedcracked gas to be spouted from the spout 47, at a velocity higher thanthe superficial gas velocity in an empty column, Uo (m/sec), of thecracked gas fed from the spout 41. When the process of this invention ispractised by employing the spouted bed type quenching vessel 39 shown inFIG. 2, the particle size of the solid particles in the spouted bed Scan be optionally adjusted by controlling the velocity of steam orrefined cracked gas to be injected from the spout 47, and only coarsenedparticles whose size exceeds a certain prescribed level with adhesion orsticking of carbon and tar thereon, can be selectively withdrawn fromthe spouted bed S efficiently.

In a preferably embodiment of the process of this invention, the hightemperature cracked'gas is spouted from the bottom of a vesselcontaining solid particles to thereby fluidize the solid particles andmove them upwardly together with the cracked gas, and this upward flowof the fluidized solid particles and the cracked gas is disturbed in aposition spaced a certain distance from the spout for the cracked gas.

In the above embodiment, a part of the upward flow of the fluidizedsolid particles and the cracked gas is shifted in the lateral ordownward direction to cause turbulent flows, whereby it is possible toincrease the swelling height of the spouted bed, maintain agood spoutedcondition in the bed and to prolong the contact time between the crackedgas and solid particles, with the result that it is possible to furtherimprove the efficiency of catching carbon and tar contained in thecracked gas.

One or a plurality of baffle plates may be provided spacedly in thelongitudinal direction to disturb the upward flow of the fluidized solidparticles and the cracked gas. For instance, one or more baffle plates55 having a plurality of holes 54, such as shown in FIG. 3, may beprovided in spouted beds S and S in spouted bed type quenching vessels 1and 39 illustrated in FIGS. 1 and 2. For the provision of such baffleplates a supporting rod 56 such as shown in FIG. 4 may be used. In thiscase, it is desired that the superficial gas velocity in an emptycolumn, Uo (m/sec), of the cracked gas is maintained at 2-5 m/sec andthe size of the solid particles in the bed is within a range of 1-2 mm.It is also preferred that the total cross-sectional area of theeffective interseption by the baffle plate is %-l/6 of the totaleffective cross-sectional area of the vessel 1 and 39.

Instead of the above-described baffle plate 55, one or a plurality ofcircular tubes 57 such as shown in FIGS. 5 and 6 may be provided. Thecircular tube is mounted vertically in the spouted bed type quenchingvessel in a manner such that the lower end thereof is in a positionspaced from the spout for the cracked gas with a distance of 300-800 mmmeasured longitudinally and the upper end thereof is in a position levelwith the highest end of the spouted bed of the solid particles formed inthe vessel. It is preferred that thediameter and number of tubes 57 areso selected that the corresponding diameter determined by the tubes [4 Xcross-sectional area of vessel/(vessel length immersed in spouted bedtube length immersed in spouted bed)] will be 100-200 mm. In thisembodiment using such circular tubes 57, the contact efficiency betweenthe cracked gas and solid particles can be increased and the efficiencyof catching carbon and tar contained in the cracked gas can be alsoincreased.

In still another embodiment of this invention, solid particles to whichcarbon-and tar have adhered and stuck are taken out from theabove-described spouted bed, introduced into a second vessel andfluidized into the second vessel by means of an oxygen-containing gas,and carbon and tar which have adhered and stuck to surfaces of the solidparticles are burnt out from the solid particles, which are then cooledand recycled to a first vessel, namely the spouted bed type quenchingvessel.

For conducting this embodiment, a regenerator 16 for regenerating solidparticles, which is shown in FIG. 1 is used. Solid particles which havecaught carbon and tar thereon and are withdrawn from the spouted bedtypequenching vessels 1 and 39 shown in FIGS. 1 and 2 are introduced'intothe regenerator from a conduit 35 in FIG. 1 or from'a conduit 53 via atube 51 and a valve 52 in FIG. 2. Solid particles fed to the regenerator16 are kept in the fluidized state by means of an oxygencontaining gassuch as air fed from a conduit 17 through a gas distributor 18, or theyare forcibly agitated by means of an oxygen-containing gas such as airfed from a gas spout 20 via'a conduit 19. Carbon and tar which havestuck and adhered to the particle surface are burnt out at a temperatureof 800-l,000 C. by the oxygen-containing gas, whereby the solidparticles are regenerated. If desired, it is possible to conduct thecombustionof carbon and heavy tar by injecting a fuel such as heavy oil,naphtha and crude oil from a fuel spout 22 and burning it in theregenerator 16.

The solid particles from which carbon and tar have been removed intheregenerator 16 are fed to a solid particle cooling vessel 27 via aconduit 25, a valve 26 and a conduit 36. The heat of combustiongenerated by the burning of carbon and tar in the regenerator 16 isrecovered in the form of steam by means of a waste heat recovery system24 mounted in the upper portion of the regenerator 16. The waste gasfrom the regenerator 16 is discharged via conduits 23 and 31.

Solid particles fed into the solid particle cooling vessel 27 arefluidized by means of air fed from a gas distributor 28 through aconduit 29 and cooled. The waste gas from the cooling vessel 27 isdischarged through conduits 30 and 31.

Solid particles which have been cooled in the solid particle coolingvessel 27 pass through a conduit 32, a valve 33 and a conduit 37, andthen are fed to the hopper 5 via a backet elevator 34 and a conduit 3.

In the spouted bed type quenching vessels of FIGS. 1 and 2 suitable forthe practice of the process of this invention, the number of the crackedgas spout 9 or 41 is not limited to one, but 2 or more spouts may beprovided. It is also possible to provide a plurality of nozzles 13 or 43on the side wall of the spouted bed type quenching vesselv l or 39.

The process of this invention has been described by referring to FIGS.1, 2, 3, 4, 5 and 6, but the process of this invention is not limited toembodiments using devices shown in these FIGURES.

In accordance with the process of this invention, both quenching of thehigh temperature cracked gas product and removal of carbon and tar canbe accomplished at the same time, and the stickiness of heavy tar isskillfully utilized for removal of carbon. Further, in the process ofthis invention, it is quite unnecessary to conduct the treatment ofcleaning a great amount of a contaminated washing liquid such as wateror a hydrocarbon, and the quenching of the high temperature cracked gasproduct and the removal of carbon and tar can be efficiently attained byspraying a small amount of water or a liquid hydrocarbon. Still further,the temperature of the spouted bed can be easily controlled bycontrolling the amount of such liquid sprayed, and the cracked gasproduct can be quenched to a desired temperature. Moreover, inaccordance with the process of this invention, the operations ofwithdrawing solid particles which have caught carbon and tar, from thespouted bed and regenerating them for recycle are very easy, and heatgenerated by combustion of carbon and tar can be efficiently recovered.Furthermore, in the process of this invention it is unnecessary toemploy a gas distributor, the use of which is indispensable in theconventional process utilizing a fluidized bed. Accordingly, in theprocess of this invention clogging of the quenching apparatus, which isfrequently brought about in the process using a conventional fluidizedbed, does not occur, and the maintenance of the equipment can be madewith ease. These are typical instances of industrial effectsand-advantages attained by the process of this invention.

This'invention will now be described more specifically by referring toexamples. 1

EXAMPLES I TO 5 A high temperature cracked gas product of the followingcomposition obtained by the thermal cracking of Minas crude oil wastreated by employing a spouted bed type quenching vessel of a modelshown inFIG. 1, which was provided with a cracked gas spout 9 of aninner diameter of mm, a conduit 14 of an inner diameter of 41 .6 mm forwithdrawing solid particles on which carbon and, tar have been caught, aconduit 7 of an inner diameter of 41.6 mm for feeding solid particles, anozzle 13 of an inner diameter of 1.5 mm for feeding water or liquidhydrocarbon, a conduit 11 of an inner diameter of 4.5 mm for feedingsteam or refined cracked gas to be used for spraying water or liquidhydrocarbon, and a conduit 8 of an inner diameter of 155.2 mm forwithdrawing the treated cracked gas product; the vessel 1 had an innerdiameter of 450 mm and a height of 2,150 mm.

Cracked Gas Product Composition Components by volume H, 7.0 CH 9.5 C,H,0.4 C,l-1. 15.4 C,l-l, 1.7 C,l-l 5.1 C l-l. 0.2 C l-l, 1.0 C l'l 1.1 CO6.0 CO, 13.2 0, 0.1 N, 0.2

light oil (boiling point' lower than 150C.) 0.7

heavy oil (boiling point of 150 300C.) 0.6

tar (see Table 1) carbon (see Table l) steam 37.8

As solid particles to be fluidized, particles of mullite (3Al O 2SiOwere used having a diameter of 1-2 mm, and solid particles which hadcaught carbon and tar thereon were regenerated by an apparatus such asshown in FIG. 1, and recycled and used repeatedly.

The inclination angle of the frustoconical bottom wall (divergent angleat the spout portion) of the spouted bed type quenching vessel 1 wasadjusted to 60.

The continuous operation was conducted for 72 hours under conditionsindicated in Table l and the results shown in Table l were obtained.

In Examples 1 to 3, the resident amount of the solid particles was keptconstant, but the temperature of the spouted bed differed. ln Examples 4and 5,-the temperature of the spouted bed and the resident amount of thesolid particles were made constant, but the amount of solid particlesrecycled differed.

TABLE 1 Ex. Ex. 1 2

Ex. Ex. 3 4

Operation Conditions cracked gas temperature (C.) 800 800 800 800 800tar content in cracked gas 20.3 20.3 20.3 20.3 20.3

(s/ dry s carbon content in cracked gas (g/Nm' dry gas) 47.3 41.3 47.347.3 47.3 feed rate of cracked gas (mlhr at 800C.) 1482 1482148214821482 velocity of cracked gas at spout outlet (m/sec) 43.3 43.3 43.343.3 43.3 amount sprayed of water (kg/hr) 114.1 97.9 82.4 97.9 97.9amount of steam for waterspraying (kg/hr) 38.1 32.6 27.5 32.6 32.6amount of solid particles 90 90 90 90 90 resident in bed (kg) amountrecycled of solid particles (kg/hr) 120 120 120 90 150 feed rate ofsolid particles (kg/hr) 3 3 3 3 3 superficial gas velocity in an emptycolumn (m/sec) 2.26 2.32 2.37 2.32 2.32

Results temperature of treated cracked gas at vessel outlet (C.) 350 400450400 400 tar content in treated cracked gas (g/l lm dry gas) 4.0 6.17.3 6.3 5.9

carbon content in treated cracked gas(g/Nmdry gas) 7.1 11.8 14.7 12.311.3 amount of tar caught on solid I particles (g/kg solid particles)22.0 19.3 17.6 25.3 15.6 amount of carbon caught on solid particles(glkg solid particles) 54.6 48.2 44.3 63.3 39.0

EXAMPLES 6 AND 7 A high temperature cracked gas product obtained by thethermal cracking of Minas crude oil was treated by using the spouted bedtype quenching vessel 1 used in Example 1, in which two baffle plates,shown in FIG. 3, of an inner diameter of 240 mm having 4 holes of aninner diameter of 50 mm were provided. As is illustrated in FIG. 4, oneof the baffle plates was positioned 745 mm above the spout 9 forinjecting the cracked gas and other was positioned 1,195 mm above spout9. As the solid particles, particles of mullite (3Al O '2SiO having adiameter of l-2 mm were used. Solid particles which had caught carbonand tar thereon were regenerated in the apparatus such as shown in FIG.1, and recycled and used repeatedly. The continuous operation wasconducted for 72 hours under conditions indicated in Table 2. Theresults shown in Table 2 were obtained.

TABLE 2 Example Example 6 7 Operation Conditions cracked gas temperature(C.) 800 800 tar content in cracked gas (g/Nm dry gas) 20.3 20.3 carboncontent in cracked gas (g/Nm dry gas) 47.3 47.3 velocity of cracked gas(m /hr at 800C.) 1482 1482 flow rate of cracked gas at spout outlet(mlaec) v 43.3 43.3 amount sprayed of water (kg/hr) 97.9 97.9 amount ofsteam for spraying water (kg/hr) 32.6 32.6 amount of solid particlesresident in bed (kg) amount recycled of solid particles (kg/hr) 120- 120feed rate of solid particles (kg/hr) 3 3 superficial gas velocity in anempty column (m/sec) 2.32 "2.32 Results I temperature of treated crackedgas at vessel outlet (C.) 400 400 tar content in treated cracked gas(g/Nm dry gas) 5.3 4.5 carbon content in treated cracked gas (g/Nm drygas) 9.9 8.0 amount of tar caught on solid particles (glkg solidparticles) 20.4 21.5 amount of carbon caught on solid particles (glkgsolid particles) 50.7 53.3

1 EXAMPLE 8 The spouted bed type quenching vessel 1 of an inner diameterof 450 mm was provided with 12 of circular tubes 57 of an inner diameterof 3 inches, a thickness of 4 mm and a length of 700 mm, as isillustrated in FIGS. 5 and 6. These tubes were arranged in anequilateral triangular form of a 150 mm pitch, and they were insertedlongitudinally in the vessel 1 in a manner such that the lower endthereof would be positioned 500 mm above the spout 9 for projecting thecracked gas. With use of such vessel 1 a high temperature cracked .gasproduct obtained by the thermal cracking of Minas crude oil was treatedto remove carbon and tar. As the solid particles to be spouted in thespouted bed spherical particles of mullite (3Al,O,-2Si0,) having adiameter of 1-2 mm were used. The solid particles which had caughtcarbon and tar thereon were burnt at 900 C. by air in the regeneratorshown in FIG. 1, and the regenerated solid particles were recycled andused repeatedly. The continuous operation was conducted for 72 hoursunder conditions indicated in Table 3. Results are also shown in Table3.

TABLE 3 Example 8 Operation Conditions temperature of cracked gas (C.)800 tar content in cracked gas 20.3 (g/Nm dry gas) carbon content incracked gas 47.3 (g/Nm' dry gas) feed rate of cracked gas 1482 (m'lhr at800C.) velocity of cracked gas at spout outlet 43.3 (m/sec) amountsprayed of water (kg/hr) 97.9 amount of steam for spraying water 32.6(kg/hr)- amount of solid particles resident in 120 bed s) amountrecycled of solid particles 90 s/ feed rate of solid particles 3 s/superficial as velocity in an empty 2.32 column (m7sec) Resultstemperature of treated cracked gas at 400 vessel outlet (C.) tar contentin treated cracked gas 3.6 (g/Nm dry gas) carbon content in treatedcracked gas 74 (g/Nm dry gas) amount of tar caught on solid particles(g/kg solid particles) 30.l amount of carbon caught on solid particles(g/kg solid particles) 72.1

What we claim is:

1. A process for removing carbon and tar from a cracked gas product,which comprises spouting a high temperature cracked gas productcontaining carbon and tar, formed by the thermal cracking of ahydrocarbon, from the bottom of a vessel in which inorganic solidparticles are contained, thereby forming a spouted bed of said solidparticles in said vessel; and spraying water or a liquid hydrocarbon insaid spouted bed of said solid particles to thereby quench said crackedgas product and to simultaneously deposit and stick the carbon and tarcontained in said cracked gas product onto the surfaces of said solidparticles.

2. The process claim 1, wherein said water or liquid hydrocarbon is fedin an amount sufficient to maintain the temperature of said spouted bedat 200-600 C.

3. The process of claim 1, wherein said solid particles have a diameterof 0. l-6 mm.

4. The process of claim 1, wherein said solid particles are selectedmullite particles and alumina-silica particles.

5. The process of claim 1, wherein said cracked gas "product is fed at asuperficial gas velocity in an empty column of l-lO m/sec.

6. A process for treating a cracked gas product formed by the thermalcracking of a hydrocarbon,

which comprises spouting a high temperature cracked gas produccontaining carbon and tar, formed by the thermal cracking of ahydrocarbon, from the bottom of a first vessel in which inorganic solidparticles are contained, thereby forming a spouted bed of said solidparticles in said first vessel; spraying water or a liquid hydrocarbonin said spouted bed of said solid particles to thereby quench saidcracked gas product and to simultaneously deposit and stick the carbonand tar contained in said cracked gas product onto the surfaces of saidsolid particles; withdrawing from said spouted bed the solid particleswhich have carbon and tar deposited thereon; introducing the solidparticles withdrawn from the spouted bed into a second vessel;fluidizing the solid particles in said second vessel by means of anoxygen-containing gas; burning off the carbon and tar deposited on thesurfaces of the solid articles in said second vessel; cooling the solidparticles from which the carbon and tar have been burnt off; andrecycling the cooled solid particles to said first vessel.

# II I l i

1. A process for removing carbon and tar from a cracked gas product,which comprises spouting a high temperature cracked gas productcontaining carbon and tar, formed by the thermal cracking of ahydrocarbon, from the bottom of a vessel in which inorganic solidparticles are contained, thereby forming a spouted bed of said solidparticles in said vessel; and spraying water or a liquid hydrocarbon insaid spouted bed of said solid particles to thereby quench said crackedgas product and to simultaneously deposit and stick the carbon and tarcontained in said cracked gas product onto the surfaces of said solidparticles.
 2. The process claim 1, wherein said water or liquidhydrocarbon is fed in an amount sufficient to maintain the temperatureof said spouted bed at 200*-600* C.
 3. The process of claim 1, whereinsaid solid particles have a diameter of 0.1-6 mm.
 4. The process ofclaim 1, wherein said solid particles are selected mullite particles andalumina-silica particles.
 5. The process of claim 1, wherein saidcracked gas product is fed at a superficial gas velocity in an emptycolumn of 1-10 m/sec.